Favipiravir and Ribavirin protect immunocompetent mice from lethal CCHFV infection

Crimean-Congo hemorrhagic fever virus (CCHFV) causes Crimean-Congo hemorrhagic fever (CCHF) in humans with high morbidity and mortality. Currently, there is neither an approved antiviral drug nor a vaccine against CCHFV. In this study, we describe a lethal model of CCHFV infection using a mouse-adapted strain of CCHFV (MA-CCHFV) in adult wild-type male mice. Infected mice developed high viral loads, tissue pathology, and inflammatory immune responses before ultimately succumbing to the infection. We used the model to evaluate the protective efficacy of nucleoside analogs monulpiravir, favipiravir, ribavirin, the antibiotic tigecycline and the corticosteroids dexamethasone and methylprednisolone against lethal CCHFV infection. Tigecycline, monulpiravir and the corticosteroids failed to protect mice from lethal MA-CCHFV infection. In contrast, favipiravir and ribavirin protected animals from clinical disease and death even when treatment was delayed. Despite demonstrating uniform protection, CCHFV RNA persisted in survivors treated with favipiravir and ribavirin. Nevertheless, the study demonstrated the anti-CCHFV efficacy of favipiravir and ribavirin in a model with intact innate immunity and establishes this model for continued development of CCHFV countermeasures.

Crimean-Congo hemorrhagic fever: A pediatric case responding to plasmapheresis treatment

Crimean-Congo hemorrhagic fever (CCHF) is a life-threatening tick-borne viral infection. The most important step in the treatment of CCHF is supportive therapy. Ribavirin is the recommended antiviral agent for infected patients. We present a case of a child who presented to our pediatric intensive care unit due to CCHF and was treated with plasmapheresis and ribavirin. A previously healthy seven-month-old male infant presented to the emergency room with a fever of 39.5 °C, nosebleed, cough, vomiting, and weakness. We decided to apply plasmapheresis treatment due to multiple organ failure associated with thrombocytopenia, acute liver failure, and a family history of death from the disease. Plasmapheresis was performed in three sessions. By the sixth day of his admission to the intensive care unit, the patient's clinical condition had improved and his laboratory values had returned to normal, so he was transferred to the infectious diseases service in stable condition.

Vector-borne viruses in Turkey: A systematic review and bibliography

Turkey serves as a natural hub for the dissemination of vector-borne viruses and provides many suitable habitats with diverse ecologies for introduction and establishment of new pathogens. This manuscript provides an updated systematic review and meta-analysis of the vector-borne viruses documented in Turkey. Following web-based identification, screening and eligibility evaluation, 291 published reports were reviewed. The publications were categorized and listed as a supplementary bibliography accompanying the manuscript. In brief, Crimean-Congo hemorrhagic fever virus (CCHFV) and West Nile virus (WNV) are currently documented as prominent tick and mosquito-borne viral pathogens in Turkey. CCHFV produces a significant number of infections annually, with severe outcome or death in a portion of cases. WNV gained attention following the clustering of cases in 2010. Exposure and infections with sandfly-borne phleboviruses, such as Toscana virus, are indigenous and widespread. Epidemiology, risk factors, symptomatic infections in susceptible hosts, vectors and reservoirs for these pathogens have been explored in detail. Detection of novel viruses in mosquitoes, sandflies and ticks from several regions is of particular interest, despite scarce information on their epidemiology and pathogenicity in vertebrates. Introduction and emergence of viruses transmitted by invasive Aedes mosquitoes constitute a threat, albeit only imported infections have so far been documented. Detection of Rift valley fever virus exposure is also of concern, due to its detrimental effects on livestock and spillover infections in humans. Vigilance to identify and diagnose probable cases as well as vector surveillance for established and potential pathogens is therefore, imperative.

Therapeutic management of Crimean-Congo haemorrhagic fever

Crimean-Congo haemorrhagic fever has been reported in more than 30 countries in Africa, Asia, the Middle East and Eastern Europe, with an increasing incidence in recent years, especially in Europe. Because no specific treatments have demonstrated efficacy, supportive treatment is essential, as well as the provision of a centre with the appropriate means to guarantee the safety of its healthcare professionals. Laboratory monitoring of thrombocytopenia, severe coagulopathy or liver failure is of critical importance. Patients with Crimean-Congo haemorrhagic fever should be admitted to High Level Isolation Units where appropriate biocontainment procedures can prevent nosocomial transmission through infected fluids or accidents with contaminated material. In case of high-risk exposures, early administration of ribavirin should be considered.

Therapeutic management of Crimean-Congo haemorrhagic fever

Crimean-Congo haemorrhagic fever has been reported in more than 30 countries in Africa, Asia, the Middle East and Eastern Europe, with an increasing incidence in recent years, especially in Europe. Because no specific treatments have demonstrated efficacy, supportive treatment is essential, as well as the provision of a centre with the appropriate means to guarantee the safety of its healthcare professionals. Laboratory monitoring of thrombocytopenia, severe coagulopathy or liver failure is of critical importance. Patients with Crimean-Congo haemorrhagic fever should be admitted to High Level Isolation Units where appropriate biocontainment procedures can prevent nosocomial transmission through infected fluids or accidents with contaminated material. In case of high-risk exposures, early administration of ribavirin should be considered.

Ribavirin for treating Crimean Congo haemorrhagic fever

BACKGROUND

Crimean Congo haemorrhagic fever (CCHF) is a tick-borne disease that occurs in parts of Asia, Europe and Africa. Since 2000 the infection has caused epidemics in Turkey, Iran, Russia, Uganda and Pakistan. Good-quality general supportive medical care helps reduce mortality. There is uncertainty and controversy about treating CCHF with the antiviral drug ribavirin.

OBJECTIVES

To assess the effects of ribavirin for treating people with Crimean Congo haemorrhagic fever.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register; the Central Register of Controlled Trials (CENTRAL); MEDLINE (PubMed); Embase (OVID); Science Citation Index-Expanded, Social Sciences Citation index, conference proceedings (Web of Science); and CINAHL (EBSCOHost). We also searched the WHO International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov for trials in progress. We conducted all searches up to 16 October 2017. We also contacted experts in the field and obtained further studies from these sources.

SELECTION CRITERIA

We evaluated studies assessing the use of ribavirin in people with suspected or confirmed Crimean Congo haemorrhagic fever. We included randomised control trials (RCTs); non-randomised studies (NRSs) that included more than 10 participants designed as cohort studies with comparators; and case-control studies.

DATA COLLECTION AND ANALYSIS

Two review authors assessed eligibility, risk of bias, and extracted data. For non-randomized studies we used the ROBINS-I tool to assess risk of bias. The main effects analysis included all studies where we judged the risk of bias to be low, moderate or high. We summarized dichotomous outcomes using risk ratios (RRs) and continuous outcomes using mean differences (MDs), and used meta-analyses where appropriate. We carried out a subsidiary appraisal and analysis of studies with critical risk of bias for the primary outcome, as these are often cited to support using ribavirin.

MAIN RESULTS

For the main effects analysis, five studies met our inclusion criteria: one RCT with 136 participants and four non-randomized studies with 612 participants. We excluded 18 non-randomized studies with critical risk of bias, where none had attempted to control for confounding.We do not know if ribavirin reduces mortality (1 RCT; RR 1.13, 95% confidence interval (CI) 0.29 to 4.32; 136 participants; very low-certainty evidence; 3 non-randomized studies; RR 0.72, 95% CI 0.41 to 1.28; 549 participants; very low-certainty evidence). We do not know if ribavirin reduces the length of stay in hospital (1 RCT: mean difference (MD) 0.70 days, 95% CI -0.39 to 1.79; 136 participants; and 1 non-randomized study: MD -0.80, 95% CI -2.70 to 1.10; 50 participants; very low-certainty evidence). We do not know if it reduces the risk of patients needing platelet transfusions (1 RCT: RR 1.23, 95% CI 0.77 to 1.96; 136 participants; very low-certainty evidence). For adverse effects (including haemolytic anaemia and a need to discontinue treatment), we do not know whether there is an increased risk with ribavirin in people with CCHF as data are insufficient.We do not know if adding ribavirin to early supportive care improves outcomes. One non-randomized study assessed mortality in people receiving ribavirin and supportive care within four days or less from symptom onset compared to after four days since symptom onset: mortality was lower in the group receiving early supportive care and ribavirin, but it is not possible to distinguish between the effects of ribavirin and early supportive medical care alone.In the subsidiary analysis, 18 studies compared people receiving ribavirin with those not receiving ribavirin. All had a critical risk of bias due to confounding, reflected in the mortality point estimates favouring ribavirin.

AUTHORS' CONCLUSIONS

We do not know if ribavirin is effective for treating Crimean Congo haemorrhagic fever. Non-randomized studies are often cited as evidence of an effect, but the risk of bias in these studies is high.

Crimean-Congo haemorrhagic fever virus: Past, present and future insights for animal modelling and medical countermeasures

Crimean–Congo haemorrhagic fever (CCHF) is a widespread tick‐borne viral zoonosis with a case‐fatality rate ranging from 9% to 50% in humans. Although a licensed vaccine to prevent infection by the CCHF virus (CCHFV) exists, its ability to induce neutralizing antibodies is limited and its efficacy against CCHFV remains undetermined. In addition, controlling CCHF infections by eradication of the tick reservoir has been ineffective, both economically and logistically, and the treatment options for CCHF remain limited. In this review, we first critically discuss the existing animal models to evaluate therapeutics for CCHF. We then review the therapeutic options for CCHF that have been investigated in human cases, followed by investigational drugs that have been evaluated in pre‐clinical studies. We highlight the importance of understanding human prognostic factors in developing an animal model for CCHF that recapitulates hallmarks of human disease and its implication for selecting therapeutic candidates.

Recent advances in research on Crimean-Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever (CCHF) is an expanding tick-borne hemorrhagic disease with increasing human and animal health impact. Immense knowledge was gained over the past 10 years mainly due to advances in molecular biology, but also driven by an increased global interest in CCHFV as an emerging/re-emerging zoonotic pathogen. In the present article, we discuss the advances in research with focus on CCHF ecology, epidemiology, pathogenesis, diagnostics, prophylaxis and treatment. Despite tremendous achievements, future activities have to concentrate on the development of vaccines and antivirals/therapeutics to combat CCHF. Vector studies need to continue for better public and animal health preparedness and response. We conclude with a roadmap for future research priorities.

Efficacy of high-dose methylprednisolone in patients with Crimean-Congo haemorrhagic fever and severe thrombocytopenia

Crimean-Congo haemorrhagic fever (CCHF) is an acute viral haemorrhagic disease that is now endemic in south eastern Iran. The most important factor associated with mortality is a platelet count of less than 50,000/mL. The purpose of this study is to compare treated cases with severe thrombocytopenia using ribavirin with high-dose methylprednisolone (HDMP) with patients receiving ribavirin without HDMP. A clinical trial was conducted for confirmed patients with CCHF and severe thrombocytopenia (platelet count less than 50,000/mL) admitted to Boo-Ali Hospital in Zahedan between January 2010 and October 2011. The intervention group was given oral ribavirin, supportive managements and HDMP and the controls were treated with ribavirin and supportive management. Following HDMP therapy in hospitalized patients with severe thrombocytopenia, the platelet count increased within 36 h and the leukocyte count within 48 h of the beginning of treatment. Fewer in the intervention group required a transfusion of blood products than in the controls (P < 0.001). No one in the intervention group died. It seems that high-dose methylprednisolone is effective in the treatment of patients with CCHF. The increased platelet count and reduction of blood product requirement for severe CCHF patients after receiving HDMP are promising results. Further investigation is necessary in order to determine the efficacy of corticosteroid and its effect on outcome.

The treatment of crimean-congo hemorrhagic fever with high-dose methylprednisolone, intravenous immunoglobulin, and fresh frozen plasma

Crimean-Congo hemorrhagic fever (CCHF) is an acute tick-borne disease caused by Nairovirus, and it is sometimes characterized by reactive hemophagocytic histiocytosis (HLH). The reasons for reactive HLH are macrophage-activating syndrome and disseminated intravascular coagulation due to cytokine storm, liver dysfunction, and endothelial damage by the virus. In this study, the effectiveness of high-dose methylprednisolone (HDMP) (5 to 30 mg/kg/d), fresh frozen plasma (FFP), and intravenous immunoglobulin (IVIG) was investigated in patients with CCHF associated with reactive HLH. Twelve patients with CCHF in association with reactive HLH were included in the study. The patients were successfully treated with HDMP to suppress the macrophage activation, FFP to treat disseminated intravascular coagulation, and IVIG to treat severe thrombocytopenia. No patients received ribavirin. Fever reduced in 1.6 ± 0.8 days, WBC count increased above 4.500/µL in 4.0 ± 2.4 days, platelet count increased above 150.000/µL in 8.5 ± 2.5 days, and D-dimer level decreased under 1 mcg/dL in 5.8 ± 3.6 days. Consequently, HDMP, FFP, and IVIG may be effective in patients with CCHF associated with reactive HLH during hemorrhagic period of the disease.

Case management and supportive treatment for patients with Crimean-Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne infection which has been increasing in Turkey and European countries since the year 2000. The disease is particularly endemic in the Middle East and in some African countries. It is also seen in European countries as a travel infection. Patients with confirmed diagnosis are usually hospitalized for monitoring, while patients with good overall condition may be monitored on an outpatient basis. Hospitals that manage CCHF should have easy access to a blood bank, and tertiary care hospitals must have a well-equipped intensive care unit. Strict blood and body fluid control precautions should be started on admission to limit CCHF exposure. The follow-up period for each patient is determined based on individual clinical status and laboratory values. Since there is no specific antiviral treatment for CCHF, supportive treatment is essential. This review highlights some of the major features of case monitoring and supportive treatment in CCHF.

Recent progress in the treatment of Crimean–Congo hemorrhagic fever and future perspectives

Crimean–Congo hemorrhagic fever (CCHF) caused by the CCHF virus, a member of the family Bunyaviridae, genus Nairovirus, is a tick-borne acute viral hemorrhagic fever with a high case–fatality rate. Ribavirin has been used as a treatment for patients with CCHF. Although the efficacy of ribavirin in the treatment of CCHF has not yet been proven conclusively, its use in the early stage of the disease is recommended. A number of clinical and virological insights into CCHF have been revealed. Virus-associated hemophagocytic syndrome has been found to contribute to the exacerbation of CCHF in some patients, and the administration of methylprednisolone at high doses was observationally undertaken in patients with CCHF and virus-associated hemophagocytic syndrome, with promising results. It is expected that effective therapeutics and preventive measures will be developed in the future.